In addition to describing the relationship between mtDNA expression and clinical outcomes, Reprogenetics and Fragouli et al. (2015) were able to establish a threshold over which no clinical pregnancy was established. These results were further validated in a prospective blinded study and independently validated using Next Generation Sequencing (NGS) analysis. The quantification of mtDNA therefore provides important information in selecting the best embryos for transfer. MitoGradeTM is a real-time polymerase chain reaction (PCR) based method developed to quantify the amount of mitochondrial DNA (mtDNA) present in human preimplantation embryos. It is believed that a chromosomally normal embryo with a MitoGradeTM score lower than the established threshold will have a higher chance of successful implantation in comparison to a similar embryo with a higher MitoGradeTM score.